Syngas comprises hydrogen (H2) and carbon monoxide (CO) and can be readily produced from either coal or methane (natural gas) by methods well known in the art and widely commercially practiced around the world. Syngas can also be produced from biomass, via a number of well-known processes.
The Fischer-Tropsch catalytic process for catalytically producing hydrocarbons from syngas was developed in the 1920's, and was used in South Africa for many years to produce gasoline range hydrocarbons as automotive fuels. Those catalysts typically comprised iron or cobalt supported on alumina or titania, and promoters, like rhenium, zirconium, manganese, and the like were sometimes used with cobalt catalysts, to improve various aspects of catalytic performance. The products were typically gasoline-range hydrocarbon liquids having six or more carbon atoms, along with heavier hydrocarbon products. More recently however, the Fischer-Tropsch process has been increasingly focused on and developed as methods for preparing the heavier hydrocarbons suitable for use as diesel fuels, and/or waxy hydrocarbon molecules suitable for conversion to clean, efficient lubricants.
A number of modern and well-known industrial processes also use syngas as a starting material for producing various oxygenated organic chemicals. For example, syngas can be readily and efficiently catalytically converted to methanol, then the methanol can be further efficiently reacted with carbon monoxide (separated from syngas) in the presence of soluble Rh/I or Ir/I catalysts to produce acetic acid, and both of these process steps are widely commercially practiced around the world.
Propane and propylene are also widely produced commercially, typically from oil, via a variety of processes commercially practiced in oil refineries. Propylene is particularly valuable for making a variety of high value downstream products, via known commercial processes, and commands a significantly higher price than propane. The vapor phase oxidation of propylene to acrylic acid with air or oxygen, over supported metal oxide catalysts is commercially practiced.
There are also some reports of direct catalytic oxidation of propane to acrylic acid. A highly selective propane to acrylic acid process could potentially be more economically attractive than a propylene-based process, because of the significant price difference between propane and propylene as starting materials.
Disclosed herein are methods related to a catalytic process that converts syngas to useful products.